The present invention relates to a brake control apparatus including a brake booster and a hydraulic modulator for regulating a brake fluid pressure and/or a brake control method useful in case of a failure in a brake booster.
A master cylinder operates in response to a driver's brake operation, and supplies a brake operating fluid toward one or more wheel cylinders. A power brake booster is a device to operate the master cylinder in addition to a driver's brake operation, and thereby assist the driver's brake operation. A widely used vacuum brake booster generally utilizes an intake vacuum of an internal combustion engine as power for the booster. In some case, a vacuum pump is utilized in substitution for the engine vacuum. However, the use of the vacuum pump tends to increase the possibility of failure in the brake booster more or less. Accordingly, a published Japanese patent specification JP-A-2001-513041 (≈WO9835867A1) shows technique of preventing a decrease of the braking force by controlling a wheel cylinder pressure with the use of a pump in an anti-lock brake control (ABS control) unit at the time of a failure in the brake booster.